Do soil lice cause yellowing?

I am a whole 13 days into the grow and I'm already experiencing a little yellowing. I have noticed that I have some bugs that like to rave on the top of the soil after watering and most sources point to soil lice. Most of my plants look all right, but I have noticed some yellowing starting from the bottom up. I just fed them for the first using Miracle Grow Bloom Booster (15-30-15) at 1/3 strength. My soil is a mix of top soil and organic potting soil with no added nutes. It looks a bit like a nitrogen deficiency, but I'll go take some pictures here in a minute and let the pros give me a proper diagnosis. Thanks for the help!

The bugs don't cause yellowing but their presence could indicate a problem. How do you determine that it is time to water? Is there soggy soil or standing water at the bottom of the pot, or in the tray it sits on?

I will also say that the soil mix has some compost in it which would invite decomposers. I had to leave my plants alone for 3 days when I went to the Summer Camp festival over the weekend and some grew tall enough to come in contact with the fluorescent tubes, but I don't think that would cause this problem.

The "pests" are very tiny "white" insects that move pretty quickly for their size and do not jump when disturbed, or so that I have seen. They also do not exhibit a larval like build. They do not come to the top of the soil unless their is some form of disturbance. My camera can't get a clear shot of the little rascals in action, but I might try to catch a few and get a diagnosis from someone around here. My soil has been pretty moist recently, so I intend to let the medium dry thoroughly before the next watering. Here are a few pictures to help out.

Yeah, definitely let it dry better. HAng a no-pest strip in your grow area if they 'bug' you (not if it's too close to your bedroom or in a living area), and keep dead leaves and spills cleaned up.

Under normal circumstances, time to water means that the top 1/4 - 1/2 inch or so of the soil is dry to the touch. They have likely been a little too moist recently. They were transplanted from plastic cups to their 4 1/4 gallon pots last Wednesday and were watered liberally before I left for the weekend and I noticed the yellowing when I got home. The stems also exhibit a pink/purplish tone, which I believe is also a symptom of nitrogen deficiency. It hasn't slowed them down too much and I've already taken measures to increase ventilation into and out of the grow area.

One last thing; after feeding them yesterday, I noticed that the run off water had a rather putrid odor. There was also a film that floated to the top of the run off and so I emptied the watering trays fearing this would invite either more pests or disease.

Okay, let's troubleshoot your real problem!
You are giving too much water. The soil looks like it's quite dense, and that means a dry surface isn't indicative of a dry pot. Feel the WEIGHT- lift the pot to determine dryness.
You should read the sticky at the top of 'basic' about continuous canopy, and the FAQ entry about potting-up. Unused soil in a pot too large for a young plant WILL stagnate and become problematic.
If you can punch a BUNCH of large holes in the sides of the pot to aid drying and root zone oxygenation, I'd do that right away.

Thanks Stinky, your wisdom is truly a saving grace! I'm sorry for not filling out the official troubleshoot form and I apologize for any irritation I may have caused. Thanks again and I'll let you know what's going on in a couple of days.

No dude, that's a totally simple problem and seeing pics is plenty. Mostly the form needs to be used when you have your plants looking crappy, not just dirt bugs.

Well, it's been about 5 days since I transplanted the 3 root strangled plants into pure potting soil. 3 of the 4 are looking decent, with the one plant originally in pure potting soil really loving life. Should I be worried leaf size has dramatically changed within the last 5 days, or does it take a little longer for roots to grasp their way into new soil? Hopefully these pics will help out. The healthy looking one has always been in potting soil, while the other was recently transplanted from a very dense organic top soil/potting soil mix.